1. Field of the Invention
The invention relates to a buckle which attaches straps in three different directions, wherein the buckle is disengaged or opened by pushing on a centrally located button or flap. More particularly, the invention relates to such a buckle having an improved latching capability.
2. Description of Related Art
Buckles for attaching straps in three different directions are known in the art. For example, my U.S. Pat. No. 5,659,931 is directed to a three-piece buckle in which a centrally disposed socket member receives a pair of plug members through open opposite ends thereof. Each of the plug members has a cross bar which is adapted to attach a strap. The socket member also defines a cross bar, but in a direction which is perpendicular to the cross bars in the plug members, for attaching a third strap in a direction which is perpendicular to the straps attached by the plug members. The socket member defines a channel therethrough which is adapted to receive a portion of the plug members when the three buckle pieces are coupled to one another. Each plug member has a tongue which extends from a base portion thereof. The tongue is adapted to be received through an open end of the socket member. Each tongue defines a latching surface, e.g. a stopping member, on it which is adapted to engage with a stopping member in the socket. The tongues are resiliently flexible, so that as they slide into the socket member their latching surfaces can snap onto the stopping members inside the socket and thereby lock the buckle in a closed position.
The three-piece buckles of the prior art are released by pushing down on a button or flap which is defined in the central region of the socket member. The flap pushes down on the resiliently flexible tongues so as to disengage the latching surfaces of the tongues from the stopping members in the socket, thereby releasing the plug members from the socket. A pair of legs, which run parallel to the tongue on opposite sides thereof in each plug member, facilitate removal of the plug members from the socket because they flex inwardly when they are inserted into the socket and thereby urge the plug members out of the socket when they are released by depression of the center push button. However, the legs do not function or cooperate in any way to latch or lock the plug members in the socket. The latching function is performed exclusively by the tongues and the stopping members in the socket.
Three-piece buckles of the aforementioned type have enjoyed great commercial success in the market because they permit straps to be attached in three different directions, which makes them particularly suitable for use in children""s seating products, especially high chairs and baby carriages. Furthermore, the center button release feature allows for simultaneous release of both plug members from the socket, and is favored by consumers over three-piece buckles wherein the pieces must be released individually.
U.S. Pat. No. 5,709,014 discloses a similar three-piece, simultaneous release buckle which may be used for children""s seating. The buckle includes a pair of plug members, each having a tongue which is adapted to be inserted into opposite open ends of a centrally disposed socket member. Each tongue defines a latching surface at its distal end which is adapted to engage with an engagement member inside the socket for locking the buckle pieces together. A centrally disposed button or flap defined in a top wall of the socket member may be pushed down on the tongues to disengage their latching surfaces from the engagement members and thereby release the buckle. As in the case of U.S. Pat. No. 5,659,931, the function of coupling the buckle pieces together is performed exclusively by the cooperation between the tongues and the engagement members in the socket.
Although three-way buckles of the aforementioned type are suitable for children""s seating, especially high chairs, one drawback associated with their use is that they are somewhat awkward to release. This difficulty is attributable to the nature of the latching mechanism, and in particular to the use of the tongues to accomplish this function. As discussed above, the tongues must be resiliently flexible so that they can flex over the stopping members or engagement members in the socket and then snap back into position. However, it is the nature of the tongues to not be that flexible because they are relatively large and are attached to the base of the plug members along a relatively long edge or surface thereof. The relatively great resistance of the tongues to flexing or bending, owing to their relatively long line of attachment to the base members, makes release of the buckle more difficult because a relatively large amount of force is necessary to disengage the latching surfaces of the tongues from the engagement members in the socket.
Another shortcoming of the three-way, simultaneous release buckles of the prior art is that the tongues do not provide for the best possible latching mechanism for the buckle. For example, in U.S. Pat. No. 5,709,014 the latching surface of the tongue is not aligned through the center axis of the tongue. Rather, the latching surface projects upwardly from the base of the tongue and is therefore spaced away from the central axis of the tongue. However, when a load or force is applied to the buckle, it will be appreciated that this force extends through the central axis of the tongues. A disadvantage of the latching mechanism of U.S. Pat. No. 5,079,014 is that because the latching surfaces of the tongue are not aligned with the central axis of the tongue, the latching mechanism does not act in alignment with and exactly opposite to the load force extending through the central axis of the tongues. This misalignment results in a somewhat diminished latching strength for buckles in general, as explained in my U.S. Pat. No. 5,794,316.
It is an object of the invention to provide a buckle which attaches straps in three different directions which is more easily releasable than the three-way buckles of the prior art.
It is a further object of the invention to provide a three-way buckle wherein the latching mechanism is more flexible than the tongues utilized in the prior art.
It is a further object of the invention to provide a three-way buckle which does not rely upon a tongue for performing the latching function.
It is another object of the invention to provide a three-way buckle which has an improved latching capability as compared to the three-way buckles of the prior art.
These and other objects of the invention are achieved by providing a three-way buckle having a socket member and a pair of plug members which may be coupled to the socket member, wherein the latching surfaces on the plug members are defined in resiliently flexible legs which extend from the base of the plug members. The latching surfaces are not defined on any tongues of the plug members. Preferably, each plug member has a pair of legs which project from the base of the plug, and each leg defines a latching surface near the distal end thereof. The socket member includes at least one post or other stopping member for engaging the latching surfaces of the legs in order to lock the plug members to the socket member. Preferably, there is a first post for engaging the legs of one of the plug members and a second post for engaging the legs of the other plug member, wherein each post is centrally situated so that it receives the legs on opposite sides thereof. Each pair of legs are spaced close enough together so that they do not fit on opposite sides of each post without bending. In this way, as a plug member is forced into the socket, the flexible legs will be forced to bend outward around the post until the plug is completely inserted into the socket, whereupon the latching surfaces of the legs will clear the post and the resiliently flexible legs will snap back into position around the post.
The plug members are simultaneously releasable from the socket because of the presence of a flap or push button which is defined in a top wall of the socket. The button includes a pair of releasing members, one releasing member for each pair of legs, which as they are pushed down into the socket are forced into a space between the legs, thereby forcing the flexible legs to bend outwardly. As the legs are forced outwardly, eventually their latching surfaces clear the post and the plug members are released from the socket. In order to facilitate this release, each post and each pair of legs are formed with cooperating inclined surfaces which allow for easy sliding movement over each other. Furthermore, the resiliently flexible nature of the legs will provide a gentle force upon disengagement of the latching surfaces from the post which causes each plug member to spring out of the socket. The button or flap is preferably coupled to a bottom wall of the socket member by a leaf spring which allows the button to be pushed down, but then return back to its original rest position for repeated use.
In a preferred embodiment, the latching surfaces defined on the legs of each plug member are V shaped and are adapted to engage with corresponding V shaped engaging surfaces on the post. This arrangement provides a latching surface area (i.e., the area of engagement between the latching surface of the legs and the engagement surface of the post) which is more evenly distributed around the top, bottom and side of each leg. This more even distribution of the latching surface area around the top, bottom and side of each leg is possible due to the generally V shape of the latching surface and the complementary V shape of the engagement surface of the post, and provides for stronger latching than the prior art.
Because the three-way buckle of the invention relies upon resiliently flexible legs for latching the plug members in the socket, as compared to the relatively inflexible tongues of the prior art, the invention affords more easy releasability of the buckle than the prior art.